Propulsion machinery for submarines



Oct. 8, 1968 G. LAGERSTROM 1 3,404,529

PROPULSION MACHINERY FOR SUBMARINES Filed June 23, 1966 INVENTOR. Quflnaf L (a crgn-O B) A W United States Patent Olfice 3,404,529 PROPULSION MACHINERY FOR SUBMARINES Gunnar Lagerstriim, Vasteras, Sweden, assignor to Allmiinna Svenska Elekn'iska Aktiebolaget, Vasteras, Sweden, a corporation of Sweden H Filed June 23, 1966, Ser. No. 559,886 Claims priority, application Sweden, June 23, 1965,

12 Claims. (Cl. 60-6) ABSTRACT OF THE DISCLOSURE The present invention relates to propulsion mechanism for submarines, especially propulsion mechanism comprising a silent propulsion unit for low speed and a second propulsion unit which alone or in combination with the first-mentioned propulsion unit is used at high speed.

Characteristic for the power need in a submarine is that the propulsion machinery of the submarine has to generate a high power for obtaining a high speed only during short time intervals. In normal operation, for more than 90% of the operation time the submarine is driven. with low power, usually with less than of the peak output. In the period of low power output it is important that the propulsion is silent.

, Different types of machine which are suitable either as low-speed or high-speed driving mechanisms are known. The problem in the present case is to obtain a combination, suitable for submarines, of a low-speed and a highspeed mechanism which demands little space, has good efiiciency, does not produce products of combustion which are difficult to handle and can to a large extent be provided withcomponents common to both mechanisms. The object of the present invention is to solve this problem, and the invention is characterised in that the propulsion mechanismof the submarine comprises a low-speed mechanism consisting of a fuel cell mechanism driven by hydrogen and oxygen and a high-speed mechanism consisting of a thermal power mechanism, preferably a turbine mechanism, of a type known per se having water as a working medium which water vapour is at least partly formed by the combination of oxygen and hydrogen.

Within the scope ofthe invention, it is in general unimportant Whatkind of thermal power mechanism is used as long as the above mentioned conditions are fulfilled. In the present stage of the art, however, a turbine mechanism is preferable to other known thermal power mechanisms and the invention will therefore in the following description for the sake of simplicity mainly be described as a thermal power mechanism of the turbine type. Due to the fact that the working medium in the turbine mechanism is water vapour formed by the combination of oxygen and hydrogen, several advantages are gained. First of all oxygen and hydrogen also constitute fuel for the fuel cell mechanism and the two mechanisms can thus be connected to the same working fluid system. Secondly very high temperatures can be obtained due to said combustion which makes it possible to build the turbine mechanism according to the same principles and for the same high temperature as a gas turbine aggregate, thereby gaining considerable thermo-technical advantages due to the high admission temperatures. Thirdly it is Patented Oct. 8, 1968 possible tocondense the working medium in the same way as in steam turbine aggregates, that is to make use of the advantages of the low terminal pressure ,characteristic for steam turbines. Fourthly the fuel for the turbine can be (hydrogenand oxygen cooled to liquid form, whereby'the pumping of the fuel supply to the turbine only requires low power. The three last-mentioned factors contribute to a high efiiciency of the turbine process, which means that the relative fuel consumption of the turbine is only slightly higher than that of the fuel cell mechanism.

The turbine mechanism, which alone or in cooperation with the fuel cell mechanism is intended to give the necessary peak output for high-speed propulsion, is designed for this purpose, preferably with considerably larger power than the fuel cell mechanism. It is, however, most suitable that the two machines simultaneously contribute to the propulsion, when peak output is required and they are therefore preferably arranged so that they are connectable for simultaneous driving of one and the same drive shaft.

For controlling the combustion temperature in the combustion chamber of the turbine mechanism, a water supply system can be used in a way known per se, the supplied water also being vapourized and constituting part of the working medium of the turbine. As the fuel cell mechanism gives water as a final product, it is particularly suitable to connect the reaction water tank of the fuel cell mechanism to said water supply system. The reaction water tank can advantageously also constitute a storage tank for the condensed working medium of the turbine mechanism.

The invention will be further described in the following with reference to the enclosed figures. FIG. 1 shows a diagram of a submarine drive mechanism according to the invention and FIG. 2 shows schematically a common power transmission for the fuel cell mechanism and the turbine mechanism.

In the figures 1 designates a fuel cell battery driven by hydrogen and oxygen which in a known way generates electric energy, which through cables 2 is lead to a DC motor 3, which directly drives the propeller shaft 4 of the submarine. Due to the fact that the DC motor 3 is directly connected to the propeller shaft a low-speed motor can be used, which gives a quieter drive as there is no noise making gearing included in the driving system.

The propulsion mechanism comprises also a turbine 5, which is connected to the propeller shaft 4 through a gear 6 and a clutch 7. When the clutch 7 is engaged the turbine 5 and the electric motor 3 simultaneously drive the propeller shaft 4 and the highest driving power is produced. When silent driving is necessary the turbine 5 and the gear 6 can be completely disconnected by means of the clutch 7.

The fuel cell mechanism and the turbine mechanism have common fuel tanks 8 and 9, one of which contains liquid hydrogen and the other liquid oxygen. The tanks 8 and 9 are vacuum insulated and provided with pressure regulating means 10. For driving of the fuel cell battery the liquid hydrogen and oxygen are led through conduits 11 and 12 to vapourizers 13 and 14 respectively and from there further along in gaseous state through conduits 15 and 16 to the fuel cell battery 1. The fuel cell battery is provided with a cooler 17, the cooling medium of which constitutes sea water which is supplied from outside through the conduit 18. In the fuel cell battery 1 the supplied hydrogen and oxygen are converted into water which through an outlet conduit 33 is led to the reaction water tank 32.

From the fuel conduits 11 and 12 branch conduits 19 and 20 are led to cryo pumps 21 and 22 respectively r 3 which'co'mpre ss the liquid fuels to a suitable pressure preferably 20 I lbars,"possibly higher. From said pumps the fuel, still in liquid state, is led through conduits 23 and 24 to a combustion chamber 25 in which the hydrogen and oxygen are allowed to react with each other forming water vapour at a very' high temperature, preferably 800 900 C. The fuel conduits 23 and 24 pass, a't'the sections 26 and 27 respectively, close to the warm parts of the combustion chamber, whereby the fuel achieves a certain pre-heating and the combustion chamher at the same time a certain cooling. From the combustion chamber the generated water vapour is led through a steam conduit 28 to the turbine and from there to a condenser 29 in which the pressure is kept very low in a known way by means of a vacuum pump 30. The condenser is cooled by sea water and the condensate is pumped by a pump 31 to the reaction water tank 32 of the fuel cell battery.

For the control of the combustion temperature in the combustion chamber 25 water is fed through a conduit 34 and this water is received from the reaction water tank 32 of the fuel cell battery. The supplied water is vapourized and fed back -to the reaction water tank 32 after it has passed through the turbine cycle.

FIG. 2 illustrates a suitable way of co-ordinating the power transmission from the fuel cell mechanism and the turbine mechanism. The electric motor 3 of the fuel cell mechanism comprises a stator 35 and a rotor 36. The stator 35 is by bearings 37 mounted directly on the propeller shaft 4. The rotor 36 is supported by a hollow shaft 38, which by bearings 39 also is mounted on the propeller shaft 4. The rotor 36 can by means of a clutch 40 be connected with the shaft 4 or disconnected from the same. If it is not necessary to disconnect the electric motor 3 from the propeller shaft 4, the clutch 40 may be rigid.

The turbine 5 is, as previously described, connected to the propeller shaft 4 through the gear 6 and the clutch 7. The shown device makes it in any easy way possible to drive the propeller shaft either by the electric motor 3, the turbine 5 or by both at the same time.

The invention is not limited to the embodiments shown but several variations and modifications are feasible within the scope of the following claims.

I claim:

1. An underwater propulsion system for submarines comprising a supply of liquid hydrogen, a supply of liquid oxygen, a fuel cell battery driven by hydrogen and oxygen, means to vapourize and distribute hydrogen and oxygen from said supplies and to conduct such vaporized gases to said fuel cell battery, an electric motor fed by said fuel cell battery for driving the submarine in the low speed range, means for connecting said motor to a propeller shaft of said submarine, a combustion chamber means generating super-heated steam by burning hydrogen and steam from said engine, and means for conneclingsaid heat engine to a pro peller shaft of said submarine.

2. A propulsion system for submarines according to claim 1, in which a water tank connected to said fuel cell battery and said condensing means receives water produced in said battery and condensing meansi 3. A propulsion system for submarines according to claim 2, in which said water supply system supplies water from said water tank. i

4. A propulsion system for submarines according to claim 1, in which said water supply system is connected to the outlet of said fuel cell battery to receive water produced therein. r l

5. A propulsion system for submarines according to claim 1, in which said means to supply liquid hydrogen and liquid oxygen from said supplies to said combustion chamber includes cryopumps.

6. A propulsion system for submarines according to claim 5, in which said pumps raise the pressure of the liquid hydrogen and oxygen at least 20 bars.

7. A propulsion system for submarines according to claim 5, in which the means to supply liquid hydrogen and oxygen to said combustion chamber includes distribution conduits which pass near warm parts of said combustion chamber to preheat said liquid gases.

8. A propulsion system for submarines according to claim 1, in which said heat engine is a steam turbine.

9. A propulsion system for submarines according to claim 1, in which both said electrical motor and said heat engine are connectable for simultaneous driving of the same propeller shaft.

10. A propulsion system for submarines according to claim 1, in which said electrical motor comprises a low speed electrical motor for directly driving said propeller shaft.

11. A propulsion system for submarines according to claim 1, comprising a clutch allowing said heat engine to be completely dis-connected from said propeller shaft.

12. A propulsion system for submarines according to claim 1, in which said electrical motor is arranged around said propeller shaft, the rotor of said motor being mounted on a hollow shaft mounted on bearings on said propeller shaft and in which there is clutch means allowing the rotor to be connected or disconnected with respect to said propeller shaft.

References Cited UNITED STATES PATENTS P I 2,149,873 3/1939 Shapiro et al 3l0.78 X 2,482,262 9/1949 Goddard 60260 3,101,592 8/1963 Robertson et al. 6039,05 X 3,134,228 5/1964 Wolansky et a1. 603,9.46 x 3,328,957 7/1967 Rose 60-3946 FOREIGN PATENTS 100,013 7/1916 Great Britain.

OTHER REFERENCES Fuel Cells With Ion-Exchange Electrolytes, Electrotechnology, June 1962,'pp'. -137. I

MARTIN P. SCHWADRQNfPrz'mdry Examine)": C. B. DORITY, Assistant Examiner. 

